Improvement in carbon-telephones



G. M. PHELPS. Carbon-Telephone.

No. 222,202. Patented Dec. 2,1879.

IJV'VEJV'TOR George. .21.

WITNESSES By his Attorneys- 1 3 QM $02 W 9% N. PETERS. PHOTO-LITHDGflAFHER, WASHINGTON D C.

Unrrnn STATES) PATENT OFFICE.

GEORGE M. PHELPS, OF BROOKLYN, NEW YORK.

IMPROVEMENT IN CARBON-TELEPHONES.

Specification forming part of Letters Patent No. 222,202, dated December '2, 1879; application filed June 4, 1879.

To all whom it may concern:

Be it known that I, GEORGE MAY PHELPS, electrician, of Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Transmitters for Electric Speaking-Telephones, of which the following is a specification.

My invention relates to and constitutes an improvement upon that class of carbon transmitters for electric speaking-telephones (shown in Letters Patent No. 214,840, granted to me April 29, 1879) in which the circuit is traversed by a continuous currentfrom a local battery, which current is thrown into waves or undulations by the action of sonorous atmospheric vibrations (caused by articulate sounds uttered in the neighborhood of the transmittingdiaphragm) acting upon a variable resistance inserted in said circuit tovary the strength or intensity of the current in a manner and form corresponding with the vibrations of the diaphragm, as is well understood.

' My present invention relates more especi ally to an improved construction of telephonic transmitting apparatus, whereby it is rendered effective and readily adjustable, while avoiding the liability of crushing the carbons, to which rigid adjusting devices are liable. Carbon-adj usting devices for speaking-telephones are not, however, new, broadly considered, one example of such devices being shown in Edisons Patent No. 203,014, granted April 30,1878. I therefore limit my claims to the specific organizations hereinafter speci- In the accompan in drawin s which exemplify the best way now known to me of carrying out the object of my invention, Figure 1 represents a plan or top view of so much of the apparatus as is necessary to illustrate my invention, with the diaphragm, mouth-piece,

and cover removed to show the internal mechdiaphragm, disk, or plate, preferablyof metal, is stretched across the case, clamped between the case and cover, and provided with the usual dampening-rings d on each side thereof. One or more carbon buttons or disks, e 0 c inclosed within a ring, F, of vulcanite, hard rubber, or other suitable insulating material, rests fiatwise upon the head Got a spindle, g, of metal, movable freely eudwise in a guideslot, a, in the casing. A plug, 01, ofwood or other suitable non-conducting material, resting upon or inserted in the upper carbon disk, bears upon the inner or under face of the diaphragm. The guidespindle passes through an opening in a stiff plate-spring, H, secured at or near one end to a boss or projection on the inner side of the case by means of a set-screw, h, or other suitable clamping device. The other end of the spring is controlled by means of a set-screw, it, passing through an opening in the casing and through a hole in one end of the spring, in

to approach by releasing the screw. It is ob-- vious that the adj ustin g-screw could work through a corresponding female screw tapped through the case, so has to force the spring forward to increase the pressure, or withdraw it to diminish it, both means of adjustment being wellknown equivalents, although the operation of one is the converse of the other.

The arrangement upon circuit is as follows: One pole of the battery is connected directly with the case A, through which and the guide spindle the current flows as well asthrough the carbons, and thence through the wirei and binding-screw I, to which thereturnwire and local battery are connected in circuit, as usual. 1

The apparatus is adapted for operation with any of the well-known telephonic receivers now in use.

The mode-of generating, transmitting, and

reproducing the rhyth mical vibrations, undulations, or waves representing articulate speech being similar to that of other telephonic apparatus needs no further elucidation here.

It will thus be seen that by means of my apparatus 1 am able to maintain the desired pressure upon the carbon and readily to adjust it without danger of crushing, as is apt to be the case where positive adjustments are employed.

I do not broadly claim a spring forming or carrying one electrode of the circuit of a telephone, and constantly pressing against the other electrode and diaphragm to maintain the required initial pressure between the electrodes and yield to the movements of the diaphragm; neither do I broadly claim a yielding weight connected with a movable electrode to resist the movement of a diaphragm and modify by its inertia the variation of pressure between the two electrodes.

1 claim as of my own invention-- 1. A carbon disk or button (constituting part of a telephonic transmitting apparatus) mounted on aspindle movable end wise through an adjusting-spring to regulate the pressure without danger of crushing the carbon, substantially as hereinbefore set forth,

2. Carbon disks (having their adjacent faces in contact) mounted on a head or guidespindle supported by and playing loosely through a spring regulated by a set-screw, to adjust the pressure on the carbons, substantially as hereinbefore set forth.

3. The combination, substantially as hereinbefore set forth, of the perforated adjustingspring, the spindle movable endwise therethrough, the carbon disks mounted on the spindle, and the regulating screw passing through the case.

4. The combination, substantially as hereinbefore set forth, of the adjusting-spring, the spindle movable therethrough, and the carbon disks and their enveloping-ring mounted on the spindle.

5. The combination, substantially as hereinbefore set forth, of the case, its guideway, the adjusting-spring, the spindle movable in the guideway and through the spring, and the carbon disks carried by the spindle.

6. The combination, substantially as hereinbefore set forth, of the case, its cover and mouth-piece, the diaphragm, the perforated adjusting-spring, the spindle movable endwise therethrough, and the carbon disks mounted on the spindle.

7. The combination, substantially as hereinbefore set forth, of the diaphragm, the adjusting-spring, the movable head, the carbons, and the plug between the diaphragm and carbons.

In testimony whereofI have hereunto subscribed my name.

GEORGE MAY PHELPS.

Witnesses:

Enos M. BARTON, FRANK L. POPE. 

